Log Message:
Update databases/elasticsearch to 1.7.3.
Fix the plugin script.

elasticsearch 1.7.3
===================

Enhancements
  Tribe Node:
    TransportNodesAction shouldn't hold on to cluster state

Bug fixes
  Internal:
    - An inactive shard is activated by triggered synced flush
    - Pending operations in the translog prevent shard from being
      marked as inactive
  Mapping:
    - Ensure more specific analyzer is used independent of the mapping order
  REST:
    - Expose nodes operation timeout in REST API
  Snapshot/Restore:
    - Snapshot restore operations throttle more than specified
  Tribe Node:
    - Increment tribe node version on updates

Upgrades
  Network:
    - Upgrade Netty to 3.10.5.final

elasticsearch 1.7.2
===================

Enhancements
  Allocation:
    - Avoid extra reroutes of delayed shards in RoutingService
  Packaging:
    - Shade joda-convert
  Query DSL:
    - Add a check if FieldMappers exists

Bug fixes
  Allocation:
    - Take relocating shard into consideration during awareness allocation
    - Take initializing shards into consideration during awareness allocation
    - Fix messaging about delayed allocation
  Internal:
    - Fix concurrency issue in PrioritizedEsThreadPoolExecutor.
  Nested Docs:
    - Nested query should only use bitset cache for parent filter
  Packaging:
    - Fix upgrade RPM script
  Plugins:
    - Plugin script: Fix ES_HOME with spaces
  Query DSL:
    - Do not track named queries that are null
    - multi_match query applies boosts too many times.
  Recovery:
    - Rethrow exception during recovery finalization even if source is
      not broken
  Snapshot/Restore:
    - Snapshot restore request should accept indices options
  Suggesters:
    - Prevent DirectCandidateGenerator to reuse an unclosed analyzer